Cabinet dryer and method



Jan. 9, 1968 E. F. BOGENBERGER 3,362,081

CABINET DRYER AND METHOD 4 Sheets-Sheet 1 Filed Nov. 29, 1965 [\VENTOR. 4/ g \l 57 424 ffiae'A/eazafe 1 E. F. BOGENBERGER 3,362,081

CABINET DRYER AND METHOD 4 Sheets-Sheet 2 Filed NOV. 29, 1965 ATTORNEYS 14 awn, a

1968 E. F. BOGENBERGER 3,362,081

CABINET DRYER AND METHOD Filed Nov. 29, 1965 4 Sheets-Sheet 3 70 64 H 1H .MIIM

INVENTOR 4z4 F 5065/V5E2 see ag aa/w AT'IORNEYS Jan. 9, 1968 ELF. BOGENBERGER 3,362,081

CABINET DRYER AND METHOD Filed Nov. 29, 1965 4 Sheets-Sheet 4 INVENTOR. 5424 F 506f/V5ERGEE 13Y% Q/M ATTORNEY-S United States Patent 3,362,081 CABINET DRYER AND METHOD Earl F. Bogenberger, Milwaukee, Wis., assignor to Fan Way Corporation, Milwaukee, Wis., a corporation of Wisconsin Filed Nov. 29, 1965, Ser. No. 510,238 11 Claims. (Cl. 34-34) ABSTRACT OF THE DISCLOSURE An upright hose dryer has a chamber with perforated bottom and top walls and a recirculation duct structure in a side wall having an impeller to draw moisture-laden air through said top wall, expel part of such air and recirculate the remainder of the air through the bottom Wall. Fresh air is added to the recirculated air and the mixture is heated. In a plenum space under the bottom wall, the impelled air is diffused by an arrangement of vaned and perforated flanges.

This invention relates to improvements in drying apparatus such as may be used in drying fire hose and other articles which lend themselves to replacement on reticulated drying frames or trays to be mounted in suitably spaced relation in a vertical drying chamber, and more particularly relates to a cabinet dryer for this purpose and a method of drying.

One of the problems that has been experienced heretofore in cabinet dryers is that some areas within the drying chamber have been less effective than others due to such factors as uneven air flow, excessive temperature differentials, and the like, so that there has been lack of uniformity in drying results.

In drying articles which must, in order to remain in prime condition and avoid deterioration, retain a substantial moisture content, a substantial problem has heretofore existed in cabinet dryers. For example, in dryingfire hose, to maintain pliability, a certain moisture content in the fabric outer protective covering is desirable, such as about 35% humidity.

It is, accordingly, an important object of the present invention to overcome the foregoing difiiculties and problems and to provide a new and improved cabinet dryer and method which will attain uniform, controlled, drying of articles, of which fire hose are an example.

Another object of the invention is to provide a new and improved drying apparatus and method attaining substantially uniform flow of drying air through a drying chamber. a

A further object of the invention is to eifect a new and improved difiusion of drying air for even flow through a drying chamber.

Still another object of the invention is to provide new, and improved method and means for reconditioning air for drying recirculation through a drying chamber.

A yet further object of the invention is to provide new and improved humidity control in a drying system of the character indicated.

Other objects, features, and advantages of the present invention will be readily apparent from the following tail view taken in substantially the same plane as FIG- URE 3.

FIGURE 4 is a fragmentary sectional detail view taken substantially on the line IVIV of FIGURE 3.

FIGURE 5 is a front perspective view of the cabinet with the doors open.

FIGURE 6 is a top plan view of the base panel of the cabinet showing the distribution of the diffuser flanges.

FIGURE 7 is an enlarged fragmentary sectional elevational view taken substantially along the line VII-VII of FIGURE 6; and

FIGURE 8 is an enlarged fragmentary sectional elevational View taken substantially along the line VIII VIII of FIGURE 6.

Desirably, a dryer 10 (FIGS. 1, 2 and 5) according to the principles of the present invention, comprises a selfcontained apparatus including a cabinet housing a vertical drying chamber 11 into which access is adapted to be gained through the front wall of the cabinet comprising a pair of hingedly mounted half-door panels 12. Aligned with the access opening for which the doors 12 provide a closure are shelf-supporting bars 13 aligned in a desirable detailed description of a preferred embodiment thereof plurality of tiers and mounted on respective left and right side wall panels 14 and 15 defining the drying chamber. Each aligned pair of the shelf-supports 13 is adapted to receive in slidable relation to the access opening a drying shelf 17 of suitable grids or reticular body construction in which an article or articles 18 are adapted to be supported for drying. The arrangement shown is especially suitable for drying a coiled fire hose. Defining the drying chamber 11 is a back wall 19 of the cabinet. At its bottom, the chamber 11 is defined by a panel 20 and at its top by a panel 21. A suitable latch structure 22 holds the doors 12 closed during operation of the dryer.

Drying air is circulated upwardly through the chamber 11, entering through perforations 23 in the bottom panel 20 and exiting through perforations 24 in the top panel 20. Coextensively under the bottom panel 20 is a plenum space 25 closed on its lower side by a base panel 27 of the cabinet. At its left side the plenum chamber is closed by the lower end portion of the rear panel 19, and at the front by a closure panel 29 under the sill for the doors 12. At the right side, the plenum space 25 opens under the lower edge of the panel 15 into a vertical passage space defined between the panel 15 and a right side outer cabinet panel 29. This passage space communicates at the top over the upper edge of the panel 15 with a drawofi space 30 over the top of the top plate 21 defined by a roof panel 31 of the cabinet and closed at the back by the upper portion of the back panel 19, at the front by a header panel 32 of the cabinet and at the left side by a left side outer panel 33 of the cabinet which provides with the panel 14 an insulating dead air space.

According to the present invention, drying air is moved in substantially balanced relation under pressure from the plenum space 25 through the perforations 23 and is sucked through the upper perforations 24 into the draw space 30, being then partially discharged to atmosphere and the remaining drawn off air reconditioned and returned to the plenum space with enough fresh air to make up for that portion which was discharged. To this end, a rotary air impeller 34 (FIGS. 2 and 3) is mounted to operate in a suitable clearance opening 35 in the side wall 29 of the cabinet preferably located about two-fifths of the distance upwardly from the base panel 27 and horizontally centered to effect outward suction of air from the passage space between the panels 15 and 29 into a reconditioning sub-housing 37 mounted on the outer side of the panel 29 and of about one-half the width thereof, enclosing the impeller at the top and extending to the base panel 27 at its lower end.

For powering the impeller 34 it is mounted on the shaft 38 driven by means of an electrical motor 39 which is supported on a bracket 40 on the outside of the subhousing 37. To confine that portion of the space between the walls 15 and 29 leading to the port 35 into a suction passage 41, a horizontal bafiie 42 is secured to and between the walls immediately below the port 35. Therefore, as the air is evacuated from the suction passage 41 and moved by the impeller 34 into the relatively smaller volume space within the sub-housing 37, pressure build-up causes a part of the moisture-laden air to exhaust through a stack 43 leading upwardly from one side of the top of the sub-housing and adapted to be connected with a suitable exhaust duct to discharge to atmosphere. The remainder of the moisture-laden air is recirculated by moving under the impeller pressure downwardly through the recirculation passage provided by the sub-chamber 37 and passes therefrom through an opening 44 opening in the lower part of the cabinet wall 29 into the portion of the between-walls space below the partition 42 affording a recirculation passageway 45 communicating throughout the width of the entrance opening into the plenum space 25. The construction and relationship and ratio of exhaust passage through the stack 43 to recirculation passage flow area taking into account proximity of the impeller 34, air velocity, direction of movement, and the like, is desirably such that about 50% of the moist air is discharged and about 50% is recirculated.

Although that portion of air which is recirculated is already at approximately drying temperature, some reconditioning by way of reheating to bring it up to optimum temperature is required. In addition, fresh, relatively dry, air is combined with the recirculated portion of the air, and such replacement air must be brought up to drying temperature. For this purpose, a suitable heater 47, such as the electric heater of Patent No. 2,623,154 is mounted in the lower portion of the recirculation passage within the sub-housing 37 such that the recirculated air will pass thereover and be reheated on its way to the outlet opening 44. In addition, fresh air is introduced in a manner to be heated by heat from the heater 47 and mixed with the recirculated air. All of the fresh air is introduced into the recirculated air in a substantially preconditioned, namely, preheated, state so as to avoid condensing moisture from the recirculated air. To this end, part of the fresh air is introduced into the recirculation passage through a preconditioning header 48, desirably comprising a horizontally elongated box-like sheet metal structure mounted on the inner face of the cabinet wall 29 adjacent to the upper end of the heater 47 and enclosing a header spaced with the wall 29 extending a substantial distance to each side of the sub-housing 37 (FIGS. 3 and 4). Fresh air inlet ports 49 open through the wall 29 into the header 48 at each side of the sub-chamber 37, desirably comprising an equal number and equal flow area at each side. Opening from the header 48 through the wall 29 into the recirculation passage is a set of ports 50 which are in suitable number and size to be of at least slightly greater aggregate flow area than the intake ports 49 so that the action of the recirculating air flowing pass a diagonal baffle 51 extending downwardly from the tops of the ports 50 and thereacross in progressively spaced relation within the recirculation passage, causes an induction of air into the header through the ports 49 and from the header through the ports 50 into the recirculation air stream at the upper end of its travel over and past the heater 47. Preheating of the air within the heater 48 is effected not only by radiant heat from the adjacent heater 47, but also by circulation of heated air past the header 48 in the circulation passage 45 as induced by limited circulation directly into the drying chamber 11 through the chamber wall panel 15 through a horizontal series of relatively small recirculation ports 52 located ad- 4 jacent to the top of the header 48. This affords, in effect, a limited bypass for heated air under the impeller pressure serving the dual purpose of heating the header 48 and dissipating radiant heat of the heater 47 from the adjacent lower portion of the drying chamber wall panel 15.

Additional fresh air to make up the difference in total volume of drying air to be circulated is introduced in a manner to be preheated as it moves in cooling relation between the wall of the subhousing 37 and the heater 47. Accordingly, a horizontal series of air intake ports 53 is provided in the wall of the subhousing 37 adjacent to the top of the heater 47. The total flow area of the ports 53 is desirably slightly over twice that of the aggregate flow area of the intake ports 49. In limited spaced relation inwardly opposite the ports 53 and between the heater 47 and the wall of the subhousing 37 is a shield panel 54 defining a preheating duct and insulating space 55 closed at the top and continuing under the heater to an eduction discharge port 57 at the lower end of the opening 44. Thus, as the recirculated air and the fresh air mixed therewith from the header 48 sweeps through the opening 44 past the narrow induction orifice 57 fresh air is drawn inwardly through the intake ports 53, coolingly sweeps through the passage 55 and is preheated before it mingles in further reconditioning relation with the partially reconditioned recirculating air. Fresh air thereby is automatically drawn into the airstream to make up for that portion of the air which was exhausted through the stack 43.

Inasmuch as the stream of conditioned air is impelled by the impeller 34 leaves the opening 44 at substantial velocity which would normally tend to focus generally toward the opposite side of the plenum space 25, means are provided for substantially equalizing and diffusing the air for substantially uniform movement upwardly through the perforations 23 in the bottom panel 20. One feature to this end comprises providing the perforations 23 in greater concentration adjacent to the intake side of the plenum space, with progressively diminishing concentration toward the opposite side. This substantially balances the upward flow area afforded by the perforations 23 in relation to the velocity of the incoming air which is greater adjacent to the intake side of the plenum space and progressively diminishes toward the opposite side.

For diffusing the air stream driven into the plenum space, diffusing means desirably in the form of a set of cooperative diffusing flanges 58 mounted in the path of the inmoving conditioned air is provided (FIGS. 2, 3 and 6). Conveniently the diffusers 58 are mounted on the cabinet base wall 27 under the drying chamber bottom panel 20 and are in such number, relative location, dimension, shape and orientation with respect to each other in the path of the incoming conditioned air as to effect such uniform distribution of the conditioned drying air within the plenum space 25 and as related to the pattern of the perforations 23, as to attain substantially uniform upward movement of the drying air through the drying chamber 11. A practical embodiment of the dryer 10, especially designed for drying fire hose, in which about seven air changes per minute are effected within the drying chamber, the air diffuser system has resulted in such even air and heat distribution that the temperature within the drying chamber does not vary substantially more than 3 at any point inside the chamber. This assures that all surfaces of the articles being dried Will be subjected to the same substantially uniform drying action anywhere inside the chamber.

As shown schematically in FIGURE 6, as the air enters substantially centrally through the entrance into the plenum chamber, the sides of the air stream strike and are deflected sidewardly by diffusers 59 and 60 located adjacent to the entrance in spaced front to rear general alignment. The central portion of the inmoving air stream impinges a diffuser 61 located inwardly and in a generally halfway orientation between the diffusers 59 and 60, providing together what may be referred to as a first line of diffusers. 'A second line of diffusers is spaced inwardly from the first line and comprises a front diffuser 62, an intermediate diffuser 68 and a rear diffuser 64. All of the diffusers are desirably formed from sheet metal and comprise upwardly extending body portions and base flanges which are suitably attached as by Welding or brazing to the base panel 27. All of the diffusers except the center diffuser 6B of the second line are of transversely arched form .and have respective lower margin central through openings 64 (FIGS. 7 and 8). The diffuser 61 also has an upper edge arcuate notch 65. The diffuser 63 which is generally straight is provided with only an upper generally V-shaped air passage notch 65. At the opposite ends of the upper margin of the diffuser 60 is provided with respective angularly bent deflector vanes 67, the forward one of which is angled upstream and the rear-ward one of which is angled downstream. On the diffuser 61 similar deflector vanes 68 are both angled upstream. Similar deflector vanes 69 on the diffuser 62 are angled downstream at the front end and upstream at the rear end, while such deflector vanes 70 on the diffuser 63 are both angled upstream. This particular relationship, as shown, has been found in practice to attain the advantageous results defined in the circulation system.

To offset the proximity of the suction passage 41 and to maintain uniformity in upward circulation within the drying chamber 11 under the substantially balanced input pressure and suction out of the top of the chamber through the perforations 24 in the top panel 21, the perforations 24 are oriented in substantially reverse order to the perforations 23 in the bottom panel. To this end the greater concentration of the perforations 2 4 is at the left side of the panel 21, that is in that portion which is remote from the suction passage 41, with progressively diminishing cross-sectional flow area afforded by the placement of the pattern of orifice 24 toward the suction passage or duct 41. For convenience in manufacture, the pattern of perforations 2:3 and 24 is identical but in reverse order in the bottom and top panels, so that the same set of punches can be utilized in producing both sets in the sheet metal panels.

Electrical controls for the motor 39 and the heater 47 are suitably provided and manually controlled from any desirable place on the cabinet 10, such as a conventional control box 7 1 (FIG. 1). In addition, automatic electrical circuit controls are desirably provided, including a suitable thermostat 72 (FIG. 2) located in the air stream, desirably adjacent to the suction duct 41 in the draw space 3 0, for automatically controlling operation of the heater 47 to maintain a uniform temperature in the drying chamber. For example, for drying fire hose a temperature of about 130 F. should be maintained with substantial uniformity. Since it is desirable to control the degree of humidity present in the dried articles, a humidistat 73 is mounted in the system, preferably in the upper portion of the suction duct 41. This controls the electrical control system to shut off the motor 39 and the heater 47 automatically when the correct degree of dryness has been attained.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In combination in drying apparatus comprising a vertical drying chamber: means in the bottom of said chamber for substantially uniform upward entry of conditioned air to circulate upwardly through the chamber; means in the top of the chamber for substantially uniform escape of air from the chamber; air moving means operative to effect substantially balanced driving of conditioned air through said bottom means and suction withdrawal of air through said top means; means cooperative with said air moving means to exhaust part of the withdrawn air to atmosphere; means cooperative with the air moving means for returning the remaining withdrawn air to said bottom means for recirculation and including means for reconditioning said remaining air; means for adding fresh air to said remaining air to replace the exhausted air; and means active following said air returning means and adjacent to said bottom means to diffuse the reconditioned air and combined fresh air before upward entry through said bottom means.

2. Apparatus as defined in claim 1, in which said reconditioning means comprise a heater adjacent to but above said bottoms, said means for adding fresh air comprise vertical passage means including a partition adjacent to and in the heating range of said heater and a wall narrowly spaced from said partition and having fresh air inlet opening toward said partition to effect preheating of the fresh air; and preheated fresh air induction orifice means below said heater leading from the space between said partition and said wall and directed toward said means to diffuse the recirculation air.

3. Apparatus as defined in claim 1, in which said fresh air adding means comprising a horizontal tempering header having fresh air inlet ports thereinto and induction means exposed to the air moved by said moving means.

4. Apparatus as defined in claim 1, including a plenum space under the bottom of said drying chamber and communicating with said returning means, and said diffusing means comprising a plurality of cooperative spaced diffuser flanges in said space located in the path of movement of the air through said space.

5. Apparatus as defined in claim 4, in which said plenum space is defined by a bottom panel on which said diffuser flanges are mounted to project upwardly, said flanges having vanes to divert air downwardly and vanes to divert air upwardly and also having openings therethrough whereby some of the air can pass through the flanges and other air is diffusedly deflected by the flanges.

6. Apparatus as defined in claim 1, in which said top means and said bottom means comprise respective perforated panels, said panels having the perforations therein disposed in complementary but reverse order comprising a pattern of perforations in the bottom panel of progressively reduced aggregate flow area from one side of the panel to the opposite side and a similar pattern of perforations in the top panel but of progressively reduced aggregate flow area from said opposite side toward said one side, said means for returning air directing such air towards the underside of the bottom panel at said one side, and said air moving means communicating in air withdrawing relation with said top panel at said one side.

7. A method of drying in a vertical drying chamber comprising: substantially uniformly distributing and driving conditioned drying air upwardly from the bottom of the chamber in drying relation to articles therein; substantially uniformly sucking the air from the top of the chamber in substantially balanced pressure relationship to the air driving pressure in the bottom of the chamber; discharging to atmosphere part of the air sucked from the top of the chamber; reconditioning the remainder of the sucked air; tempering fresh air and combining it with said reconditioned remaining air to replace the air discharged to atmosphere; discharging the combined air toward a space under said chamber bottom; and in said space diffusing the air as it moves into position for said distributing and upward driving.

8. The method of claim 7, in which at least part of the tempered fresh air is combined with said remaining air after said remaining air has been reconditioned.

9. Drying apparatus as defined in claim 1, in which said means for returning the remaining air to said bottom comprise a duct leading from said top to said bottom and including adjacent to said bottom a sub-housing, said duct having an opening therein communicating with said sub-housing and said air moving means comprising an impeller mounted to operate in said opening, a horizontal partition below said opening compelling all air withdrawn from said top through said duct to move past the impeller into the sub-housing, said means to exhaust part of the withdrawn air comprising a stack rising from said subhousing above and leading from said impeller; said means for reconditioning comprising a heater in said sub-housing below said impeller, and said means for adding fresh air including ports opening into said sub-housing.

10. Drying apparatus as defined in claim 9, in which said means for adding fresh air include a ported preheating duct and insulating space structure on the outside of said sub-housing aligned with said heater and communicating with the lower portion of said sub-housing in alignment with said means to diffuse the reconditioned air and combine fresh air.

11. Drying apparatus as defined in claim 9, in which said ported means for adding fresh air comprise a horizontal header having an induction outlet into said subhousing generally aligned with said heater and opening into the recirculation air below said impeller.

References Cited UNITED STATES PATENTS 1,295,259 12/1919 Beebee 34-2l9 X 1,488,324 3/1924 Drake 34l96 X 1,527,192 2/1925 Judelson 34-197 1,534,499 4/1925 Braemer 34l96 X 2,294,530 9/1942 Wiese 34-196 X 2,464,706 3/1949 McGraw 34197 X KENNETH W. SPRAGUE, Primary Examiner. 

